JPH07217652A - Bearing device - Google Patents

Abstract

PURPOSE:To suppress vibration while avoiding the enlargement of a device by providing a ring member sliding in relation to a shaft, being fitted to the shaft on one side or both sides of an outer cylinder. CONSTITUTION:Four ball rolling grooves 8 are formed at a shaft 1. The ball rolling grooves 8 are formed vertically by twos in one lot. It is thereby designed in such a way that the face without the presence of the ball rolling grooves 8 is as large as possible. The contact area of a ring member 7 is therefore enlarged by that part, and 'plain bearing action' by the ring member 7 is positively displayed by that part. A load ball groove 3 and a no-load ball track are formed in an outer cylinder 2 so as to form four endless circulating paths 5 jointly with the ball rolling grooves 8. The ring member 7 with such an inner diameter as to be slidable in relation to the shaft 1 is provided in line with either side of the outer cylinder 2. The ring member 7 can be also formed in such a way that the inner diameter is variable. This results in having plain bearings (sliding bearings) existing on both sides of a rolling bearing, so that rigidity is improved by that part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device.

[0002]

2. Description of the Related Art Conventionally, a shaft 31 and an outer cylinder fitted on the shaft 31 and sliding with respect to the shaft 31 have been known.
32 consists of a loaded ball track 33 and an unloaded ball track 34
There is proposed a bearing device having a ball infinite circulation path 35 constituted by and a plurality of balls 36 arranged in the ball infinite circulation path 35. Reference numeral 37 is a ball cage.

This conventionally proposed bearing device is widely used in industrial robots and the like which have been developed in recent years.

In the industrial robot, each part moves at high speed (linear motion, rotary motion), and a bearing device is used for a predetermined part of each part. The bearing device is a so-called "rolling motion" using a ball. Is a ball bearing device. This ball bearing device
Although there are various merits represented by light movement, etc., compared with the so-called "flat bearing" bearing device, there are drawbacks such as low rigidity and weakness in impact, so that, for example, each part incorporating a ball bearing device When moving at high speed, so-called cracking (vibration) or the like occurs in the respective parts.

That is, the ball bearing device has an advantage that it can move smoothly due to its low friction because the ball has a contact structure close to a point. However, the ball does not have good vibration absorbing property, and the ball is not elastically deformed. Since they are likely to occur, drawbacks based on them occur when using a ball bearing device. Especially, when each part of the industrial robot moves at high speed, this drawback is remarkable.

In order to increase the rigidity, it is possible to increase the length and diameter of the outer cylinder, but this would increase the size of the device.

It is a technical object of the present invention to provide a bearing device which solves the drawbacks of ball bearings while avoiding the problem that the device becomes large.

[0008]

The gist of the present invention will be described with reference to the accompanying drawings.

A ball endless circulation path 5 consisting of a shaft 1 and an outer cylinder 2 which is fitted on the shaft 1 and slides with respect to the shaft 1 and comprises a loaded ball raceway and an unloaded ball raceway. In the bearing device in which a plurality of balls 6 are arranged in the ball infinite circulation path 5, a ring member 7 fitted to the shaft 1 and slid with respect to the shaft 1 is provided on one side or both sides of the outer cylinder 2. The present invention relates to a bearing device.

A shaft 1 and an outer cylinder 2 which is fitted on the shaft 1 and slides with respect to the shaft 1. A loaded ball groove 3 and an unloaded ball raceway formed in the outer cylinder 2 and a shaft 1 A ball endless circulation path 5 composed of a ball rolling groove 8 formed,
In the bearing device in which a plurality of balls 6 are arranged in the ball infinite circulation path 5, a ring member 7 fitted on the shaft 1 and sliding on the shaft 1 is provided on one side or both sides of the outer cylinder 2. The present invention relates to a bearing device.

The present invention relates to a bearing device characterized in that the inner diameter of the ring member 7 in the bearing device can be varied by appropriate means.

[0012]

Operation: The outer cylinder 2 is fitted on the shaft 1 on one side or both sides,
Since there is the ring member 7 that slides with respect to the shaft 1, the rigidity becomes higher accordingly. Since the inner diameter of the ring member 7 is variably provided, the ring member 7 can be brought into contact with the shaft 1 or brought into non-contact with the shaft 1 arbitrarily.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings illustrate one embodiment of the present invention and will be described below.

Although the drawings show the case where the present invention is applied to the spline in which the ball rolling groove 8 is formed on the shaft 1, the present invention may be applied to a bush in which the ball rolling groove 8 is not formed. is there.

A shaft 1 having a perfect circle shape is provided. Because it is a perfect circle,
High accuracy is maintained and processing is very easy. The illustrated four ball rolling grooves 8 are formed on the shaft 1. As shown in FIG. 4, the two ball rolling grooves 8 are formed together in the vertical direction, and the ring rolling member 8 is designed so that the surface where the ball rolling grooves 8 do not exist is as wide as possible. The abutting area of 7 becomes wider by that amount, so that the "plain bearing action" by the ring member 7 can be reliably exerted.

An outer cylinder 2 is provided. A loaded ball groove 3 and an unloaded ball raceway are formed in the outer cylinder 2, and these balls and the ball rolling groove 8 form four infinite ball circulation paths 5. A ring member 7 having an inner diameter that is slidable with respect to the shaft 1 is continuously provided on both sides of the outer cylinder 2. The ring member 7 may be configured so that its inner diameter is variable. The structure in which the inner diameter of the ring member 7 is variable may be any structure such as a structure in which a split ring is adopted and the split rings are brought into contact with or separated from each other by a hydraulic mechanism or the like.

Reference numeral 4 is a ball retainer, 9 is a fastening ring,
10 is a rubber ring and 11 is a flange.

Since this embodiment has the above-mentioned structure, it naturally functions as a rolling bearing, and since there are plain bearings (sliding bearings) on both sides of the rolling bearing, the rigidity is improved accordingly. To do. Specifically, the rigidity in the pitching direction and the radial direction is improved, so that accurate and smooth high speed movement can be achieved even when the present embodiment is used for a portion that moves at high speed.

Further, if the inner diameter of the ring member 7 is made variable, for example, when the present embodiment is incorporated in a certain device, the outer cylinder 2 has a large inertia force at the start and end of the movement. Since a load is applied and vibrations and the like are likely to occur, the inner diameter of the ring member 7 can be contracted and brought into contact with the shaft 1, and the "flat bearing action" of the ring member 7 can be exhibited. That is, only "rolling bearings" are properly used for each usage condition.
The combination of "rolling bearing" and "flat bearing" can be selected.

The ring member 7 having a variable inner diameter allows the sliding resistance of the outer cylinder 2 in the traveling direction to be arbitrarily set.
Therefore, the feature that the sliding condition of the outer cylinder 2 can be easily adjusted can be exhibited.

[0021]

As described above, according to the present invention, since the rolling bearing and the plain bearing are combined with each other, it is possible to provide a bearing device which can exhibit the advantages of both the rolling bearing and the plain bearing.

[Brief description of drawings]

FIG. 1 is a front view in which a part of a conventional example is cut away.

FIG. 2 is a side view in which a part of the same is cut away.

FIG. 3 is a front view in which a part of the present embodiment is cut away.

FIG. 4 is a sectional view taken along the line AA in FIG.

[Explanation of symbols]

 1 shaft 2 outer cylinder 3 load ball groove 5 ball infinite circulation path 6 ball 7 ring member 8 ball rolling groove

[Procedure amendment]

[Submission date] February 18, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (3)

[Claims] 1. An infinite ball circulation path composed of a loaded ball raceway and an unloaded ball raceway, which comprises a shaft and an outer cylinder fitted on the shaft and slidable with respect to the shaft. A bearing device in which a plurality of balls are arranged in an infinite circulation path, wherein a ring member that is fitted to the shaft on one side or both sides of the outer cylinder and that slides with respect to the shaft is provided. 2. A loaded ball groove and an unloaded ball raceway formed on the outer cylinder, the loaded ball groove and the unloaded ball raceway being formed on the shaft and fitted on the shaft and sliding relative to the shaft. In a bearing device having a ball infinite circulation path composed of a moving groove and a plurality of balls arranged in the ball infinite circulation path, a shaft is fitted on one side or both sides of the outer cylinder, with respect to the shaft. A bearing device comprising a sliding ring member. 3. The bearing device according to claim 1, wherein the inner diameter of the ring member in the bearing device is variable by an appropriate means.